1. Field of the Invention
The present invention relates to an information processing system and an information processing method, and a program with which an encode parallel processing is executed.
2. Description of the Related Art
Up to now, an authoring apparatus used in a creating site of recording media such as an optical disk performs an encode processing (compression encode processing) by using, for example, an MPEG (Moving Picture Experts Group) standard on each of video data, audio data, and the like. Then, the authoring apparatus multiplexes the respective encode data obtained from results of the respective encode processings and records this multiplexed stream on the recording media.
Such an authoring apparatus allocates the bit amount that can be recorded on the recording media to each of the video data, the audio data, and the like and performs the encode processing so that the data falls within the allocated bit amount.
As an encode method for the video data, so called “two-path encode” has been proposed (for example, see Japanese Unexamined Patent Application Publication No. 2000-278042). The two-path encode is a method composed of a tentative (preliminary) encode processing and an actual encode processing.
Hereinafter, while the tentative encode processing is referred to as encode processing for the first path and the actual encode processing is referred to as encode processing for the second path, an outline of the two-path encode will be described.
An encoder performs the encode processing for the first path in which a constant encode condition is held on a series of encoding target video data. At this time, various pieces of data obtained at the time of the encode processing for the first path such as, for example, the generated bit amount, are sequentially detected in units of the frame.
Next, on the basis of the generated bit amount detected in this manner in units of the frame, the encoder performs the bit allocation for each of the frames constituting the video data. In other words, the encoder sets a target bit amount utilized in the encode processing for the second path in units of the frame.
Furthermore, the encoder assigns a picture type used in the encode processing for the second path. The assignment of the picture type refers to an assignment of an encode type to the respective frames.
To be more specific, in the MPEG, on the basis of any one of encode types including an I picture (Intra-Picture), a P picture (Predictive-Picture), and a B picture (Bidirectionally Predictive-Picture), the respective frames are encoded. The I picture refers to an encode type in which the image data of one frame is encoded as it is without utilizing the image data of other frames. In other words, the I picture refers to an encode type of an intra-frame encode processing. Also, the P picture and the B picture refers to an encode type of an in-frame encode processing. In other words, the P picture basically refers to an encode type in which a difference (predictive error) between the image data for one frame and image data for a predictive frame of the I picture or the P picture preceding the relevant image data in terms of time is obtained, and the difference is encoded. Also, the B picture basically refers to an encode type in which a difference (predictive error) between the image data for one frame and image data for a predictive frame of the I picture or the P picture preceding or following the relevant image data in terms of time is obtained, and the difference is encoded.
Therefore, the assignment of the picture type refers to an assignment of the respect frame to any of the three encode types including the I picture, the P picture, and the B picture. In other words, the assignment of the picture type can also be a configuration setting of the respective GOPs (Group Of Picture).
In this manner, after the encode processing for the first path is performed, by utilizing the processing result, the setting of the target bit amount or the assignment of the picture type is performed in units of the frame.
Next, the encode conditions including at least the picture type and the target bit amount for each frame are set, and the encode processing for the second path is executed while following the encode conditions.
That is, the encoder performs the encode processing for the second path on the video data that is the same as that for the first path and outputs the thus obtained encode video data. In more detail, the encoder sequentially encodes the data in each of the frames constituting the video data so that the data has the target bit amount at the assigned picture type. As a result, a bit stream formed by continuously arranging encode frame data of any one of the I picture, the B picture, and the P picture is output as encode video data from the encoder.
Also, as another encode method for the video data is disclosed, for example, in Japanese Unexamined Patent Application Publication No. 2002-326864 and also in Japanese Unexamined Patent Application Publication No. 2001-53570.
A method disclosed in Japanese Unexamined Patent Application Publication No. 2002-326864 is a method in which the following first to third processings are executed in the stated order. In other words, the first processing is a processing of performing the encode processing for the first path on all sections of video data. The second processing is a processing of partly performing the encode processing for the second path on data in a particular section among the video data. The third processing is a processing of replacing only the data in the particular section among the encode video data for the first path by the encode video data for the second path, and outputting the thus obtained data as the final encode video data.
In addition, a method disclosed in Japanese Unexamined Patent Application Publication No. 2001-53570 is the following method. In other words, a method of setting the target bit amount for decreasing the assignment amount in a section where no problem occurs even when the bit amount is reduced among the encode video data for the first path and assigning the relevant bit amount to another section where a problem is generated and performing the encode processing for the second path on the basis of the target bit amount is disclosed in Japanese Unexamined Patent Application Publication No. 2001-53570.
In this way, the encode processing involves high load for the bit amount computation and the like. For this reason, for example, in a case where the encode is performed on the basis of MPEG-4 AVC (H.264/AVC) which is one of codecs adopted by Blu-Ray (trademark), as the computation processing load is higher as compared with MPEG-2 adopted by DVD (Digital Versatile Disc), the encode processing time period is stretched.
In order to cope with this situation, a method of shortening the encode processing time period is proposed by distributing the encode processings to perform processings in parallel. For example, by preparing a plurality of encoding PCs (Personal Computer) having the same conditions, a material is evenly assigned by the number of the encoding PCs. As the parallel processing is executed, the H.264/AVC encode is efficiently processed, and it is possible to shorten the encode time period (see also Japanese Unexamined Patent Application Publication No. 2006-74461).